Fluid bed processor



Feb. 17,1970 J. T. GECEWICH ETAL 3,495,336

' FLUID BED PROCESSOR Filed June 30. 1967 4 :li j g- L E mvmons JO 2'GECEW/CH 00 L0 5'. METHE'IVY MMMiM ATTORNEYS m il In" United StatesPatent 3,495,336 FLUID BED PROCESSOR John T. Gecewich, Maple Heights,and Donald E.

Metheny, Lakewood, Ohio, assignors, by mesne assignments, toBartlett-Snow, a Division of Bangor Punta Operations, Inc., Bangor,Maine, at corporation of New York Filed June 30, 1967, Ser. No. 650,390Int. Cl. F26b 17/10 US. CI. 34-57 6 Claims ABSTRACT OF THE DISCLOSURE Afluid bed processor having a grid separating the bed from a plenumtherebeneath with a plurality of tuyeres in the grid for fluidizing thebed, each tuyere comprising a stud loosely fitted in an aperture in thegrid and having limited axial movement in such aperture, a pin in thestud beneath the grid and a washer on the stud above the grid, thetransverse dimension from the side of the stud to the opposite edge ofthe washer being such as to preclude flow of solids to the plenum in theopen position of the tuyere regardless of the position of the stud inthe aperture.

This invention relates generally as indicated to a fluid bed processorand more particularly to an improved tuyere or nozzle construction forfluidizing the bed. Heretofore, grids supporting the bed of fluid bedprocessors have been provided with caps or nozzles which are generallyscrewed into the grid plate and are provided with holes drilled ormachined therein either radially or tangentially to obtain properfluidization of the bed. The wall thickness of such nozzles generallyrequire to be substantial so that when the processor is down, the solids0f the bed will not flow back through the nozzle and into the plenum.Either the wall thickness must be willcient so that the angle of reposeof the solids of the bed will not permit backflow through the nozzle orspecial baflies or other types of construction are provided. Needless tosay, such machined and drilled nozzles which are threaded into the gridplate are costly to construct and replace.

-It is accordingly a principal object of the present invention toprovide a tuyere for a fluid bed processor which will effectivelyfluidize the bed and yet be of a very economical construction.

Another principal object is the provision of a tuyere for a fluid bedprocessor which when the processor is down will positively close thegrid to prevent flow of solids into the plenum.

Another object is the provision of a tuyere for a fluid bed processor inthe form of a check plate type valve.

A further object is the provision of a tuyere for a fluid bed processorhaving simplified easily replaceable components.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andthe annexed drawing setting forth in detail a certain illustrativeembodiment of the invention, this being indicative, however, of but oneof the various ways in which the principles of the invention may beemployed.

In said annexed drawing:

FIG. 1 is a fragmentary side elevation of a fluid bed processor inaccordance with the present invention;

FIG. 2 is an enlarged vertical section of the grid of the processorillustrating the tuyere of the present invention; and

FIG. 3 is a view similar to FIG. 2 illustrating the tuyere oil-centerwithin the aperture of the grid plate.

Referring now to the annexed drawing and more particularly to FIG. 1which illustrates what might be termed a typical fluid bed processor,such processor comprises a vessel 1 into which the solids constitutingthe bed are fed by screw feeder 2 through inlet passage 3. Outletpassage 4 is provided for such solids. The bed of solids is supported ona grid plate '5 having a plurality of tuyeres therein indicatedgenerally at 6. Such tuyeres may, for example, be spaced on centers offrom about 3 to about 7 inches in the grid plate 5. Beneath the gridplate 5 is a plenum chamber 8 provided with access door 9. A combustionchamber 10 is connected to the plenum and a burner 11 having flanged gasinlet 12 is mounted on the end of the combustion chamber. Air inletpassage 13 connected to the burner is also connected to the outlet of aturbo-compressor 14 mounted on stand 15. Air is drawn into the inlet 16of the compressor 14 and passes through the burner 11, the combustionchamber 10 and into the plenum 8 to pass upwardly through the tuyeres 6to fluidize the bed of solids in the vessel 1. The exhaust stack 17 isconnected to a cyclone separator in conventional manner to remove fines.Other forms of fluid bed processors may, of course, utilize the presentinvention.

Referring now more particularly to FIG. 2, it will be seen that the gridplate 5 is provided with a plurality of apertures 20 in which aresituated the check plate tuyeres 6. Each tuyere comprises a stud 21which may, for example, be a stainless steel buttonhead rivet. Below thegrid plate 5 the stud is provided with a transverse roll pin 22extending through transverse aperture 23 in such stud. Above the gridplate '5 the stud is provided with a stainless steel Washer 24 beneaththe head 25 of the stud.

In the illustrated embodiment, the apertures 20 in the grid plate 5 may,for example, be 1% inches in diameter. The stud 21 may have a diameterof /2 inch or slightly less than half the diameter of the aperture. Thepin 22 may be approximately 2 inches long, while the washer 24 may havean CD. of approximately 2 /2 inches with a inch ID. The washer may besimply fitted loosely on the stud or may be tack welded thereto. Thehead 25 of the stud together With the washer 24 forms a cap over theaperture 20 which will be opened upon the application of pressure fromthe plenum 8. The cap is of sufficient diameter, i.e. the diameter ofthe washer, to extend beyond the angle of repose of the solids of thebed regardless of the position of the stud within the aperture. Thus, asseen in FIG. 3, with the stud 21 against one side of the aperture 20,the opposite edge 26 of the washer 24 will extend beyond the angle ofrepose indicated at 27 struck from the opposite top edge of the apertureindicated at 28. Accordingly, regardless of the position of the washerand the stud on which it is positioned, the washer or cap of the tuyerewill always overlie the aperture sufficiently to prevent backflow ofsolids into the plenum when the fluid bed processor is down. If for somereason a negative pressure is created in the plenum 8, the check valveeffect of the check plate tuyere 6 will, of course, immediately closethe apertures 20 preventing the solids from being drawn through to theplenum.

The tuyeres, of course, can readily be replaced simply by knocking outthe pin 22 from the aperture 23 of the stud. All of the parts of thetuyere, of course, may be purchased items and no machining or specialmanufacturing is required. Moreover, the substantial clearance betweenthe aperture and the stud prevents cocking of the tuyere so that it isfree to move within the aperture both for limited axial movement asdictated by the position of the pin 22 and for lateral movement as seenin FIG. 3. With a /2 inch grid plate, the maximum clearance at the edgeof the washer 24 between the top of the grip plate and the underside ofthe washer may be on the order of .1454 inch.

It can now be seen that there is provided a simplified economical andefficient tuyere for fluid bed processors which will preclude backfiowof solids to the plenum.

Other modes of applying the principles of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchmay be employed.

We, therefore, particularly point out and distinctly claim as ourinvention:

1. In a fluid bed processor, a grid supporting the bed with a plenumtherebelow, a plurality of apertures in said grid, and check platetuyeres axially movable n such apertures permitting gas flow from saidplenum into said bed in response to pressure from said plenum butpreventing the bed from dropping through said grid during shut-down.

2. A fluid bed processor as set forth in claim 1 wherein said checkplate tuyeres each comprise a stud extending axially of an aperture, acap on said stud overlying such aperture, and means limiting such axialmovement of said stud within such aperture.

3. A fluid bed processor as set forth in claim 2 wherein the diameter ofeach said stud is substantially less than the diameter of the aperture.

-4. A fluid bed processor as set forth in claim 3 wherein the diameterof the cap on said stud is sufficiently greater than the diameter of theaperture so that when the stud is adjacent one side of the aperture, theopposite edge of the cap will extend beyond the angle of repose of thesolids of such bed struck from the opposite top edge of the aperture.

5. A fluid bed processor as set forth in claim 2 wherein said lastmentioned means comprises a pin extending transversely of said studbeneath the aperture.

6. A fluid bed processor as set forth in claim 2 wherein said capcomprises a head on said stud, and a washer positioned on said studbeneath said head.

References Cited UNITED STATES PATENTS 2,745,861 5/1956 Bodine 23--2882,913,318 11/1959 Erasmus et al. 23-284 3,040,439 6/1962 Frost 34-573,183,064 5/1965 Sigsworth 23-284 J. SPENCER OVERHOLSER, PrimaryExaminer J. S. BROWN, Assistant Examiner US. Cl. X.R.

